The present invention relates to a method and apparatus for manufacturing bags with strap shaped carrying handles.
Bags made of paper, foil material or the like are largely being used for packaging purposes or, if provided with handles, as shopping bags.
Prior known in the art are bag making machines of the type in which bags are in a first continuous process manufactured without handles by cutting blanks to any predetermined size from paper webs as well as by folding and bonding said blanks. The last station in such bag making machines is usually a bottom folding drum in which the bag bottoms are formed. The bags leave the bag machine in a dead flat position and with their bottoms forward.
It is a freqently adopted practice to pass the bags to a stacker station immediately after completion thereof in which they are collected into stacks and if so required into larger size packs.
Strap shaped handles may be bonded to the bags as carrying aids and specifically in the case of environmentally acceptable paper bags mostly consist of multilayered paper strips folded into a U, shaped configuration. By the end portions of their parallel legs, hereinafter referred to as attachment portions-- these strips are bonded to the bags such that U-shaped handle portions, hereinafter referred to as handles, will protrude beyond the marginal edge of the bags.
Handle bonding is generally done in a separate step using a handle assembling device. For this purpose, bags are taken from the stack, individually passed through the handle assembling unit and then immediately filled or again collected into stacks.
Since this way of proceeding is relatively complicated and expensive it would be desirable to bond the handles to the bags immediately on completion of said latter and before the bags are allowed to enter the stacker. This goal is however difficult to achieve because the projecting handles tend to aggravate bag handling inside the stacker station so that such bags provided with handles cannot be processed in conventional stacker stations.
Manufacturing processes are known from practice which provide for the handles to be bonded to those sides of the paper webs inside the bag making machine already which subsequently become the inside faces of the bags. In such cases, the handles may either protrude from the bags or the projecting handles can be turned inward such that they get entrapped between the wall members of the bag and thus are kept from hampering any of the subsequent processing steps. This way of proceeding however calls for use of a bag making machine of specific design.